#### Answer

8477 children didn't receive eye exams.

#### Work Step by Step

The way to solve this is to subtract.
To find out the number of children who didn't receive an eye exam, you must subtract the number of children who got an eye exam, from the total number of children.
So 23,156 - 14,679
Write the numbers above each other and start subtracting each digit starting from the right, If the top number is smaller, take a one away from the left digit and add 10 to your digit. Now you should be able to subtract. (See picture for exact working out)